Multi-temporal backscattering behavior of rice crop canopies based on dense medium model simulations

In recent years, efforts to study the backscattering behavior of rice crop canopies have resulted in the measurement of the multi-temporal backscattering coefficient of rice crops over various incident angles, frequencies and polarizations through the use of space-borne radars and ground-based scatterometers. With the availability of an these data, different scattering models have been developed for rice crop canopies in an attempt to further analyze the results obtained. One such model is based on the radiative transfer equations, and incorporates the Dense Medium Phase and Amplitude Correction Theory (DM-PACT) as well as the amplitude and Fresnel phase corrections to take into account coherent effects and Fresnel field effects of closely spaces scatterers, respectively. Hence, the canopy is modeled as a dense medium. An early variation of the dense medium model for rice crops employs needle-shaped scatterers to simulate the leaves of the rice plants. In this study, the phase matrix of the rice crop canopy is obtained using the scattered field of elliptic disk-shaped scatterers (with the inclusion of the Fresnel field effects) to model the leaves. This model is then used in the simulation of the backscattering coefficient of rice crop canopies at different stages of growth, through which the contribution of the different scatterers in the canopy and the backscattering mechanisms involved are then analyzed. This enables a better understanding of the multi-temporal backscattering behavior of rice crop canopies, particularly that of the sensitivity of the rice crop backscattering coefficient to the different scatterers in the medium and the input parameters of the model.